Implementation of universal two- and three-qubit quantum gates in a cavity QED

Abstract

We propose two schemes to directly implement the iSWAP and Fredkin gates by passing an atom across a multi-mode cavity QED. We have combined three types of qubits: the flying photonic qubits, the atomic qubits and the dual-rail-encoded qubits. First, we have studied the interaction of multi-level atom with multi-mode fields in a cavity by using the shore’s method. Next we have calculated the probabilities of the states of the interest as well as the fidelity of theses two schemes. An appropriate interaction times, allow us to accomplish these two gates.